Face masks are a medical product that, along with other protective elements and hygiene measures, allow us to avoid exposure and protect our surroundings from contamination with pathogens. COVID-19 infection is transmitted by droplets. These are produced by the patient when coughing or sneezing and can travel about one meter.
Carlos Cruz-Salazar, an intensive care nurse and lecturer at CEU USP, explains that filtration efficiency depends on the medical product we have available. Different types of masks prevent our environment from being infected and/or protect ourselves. Therefore, it is important to understand what kind of scenario we will be in.
TYPES AND USES OF MASKS
There are multiple protective masks on the market to deal with all types of gases and particles. But in the healthcare field, two fundamental types are used: surgical masks and high-efficiency masks. The difference between the two products is the filtration and the direction of airflow.
Surgical masks are what we should all use to prevent the spread of the pandemic in situations where we have contact with other people who are not infected. High-risk masks are indicated for all those who are in contact with COVID-19 positive individuals. Surgical masks do not filter inhaled air, therefore they do not effectively protect us. Their fundamental objective is to prevent transmission. In this fight, we are all responsible for protecting and slowing the spread of the virus. It is important to wear a surgical mask in everyday situations where we are not absolutely certain that we are immunized against the coronavirus.
High-risk or high-efficiency mask
Filtering masks are considered PPE. PPE is Personal Protective Equipment, a device worn to protect against risks that may threaten the health of the healthcare worker, in this case, exposure to the coronavirus. The higher the FFP number, the greater its filtering capacity, which can range from 70 to 98%.
High-efficiency filtering masks (FFP - Filter FacePiece) have different categories depending on the percentage of particles they are capable of retaining. Thus, we have FFP1, FFP2, and FFP3. The Ministry of Health recommends for the care of coronavirus patients a mask with a minimum filtration efficiency equivalent to FFP2 and FFP3 in case aerosols are generated.
Aerosols are small particles that travel through the air over distances greater than one meter and can be produced, for example, in a hospital setting. However, this type of airborne transmission has less impact if the patient and the personnel in contact are protected with adequate measures.
Why do COVID-19 patients not wear valved masks?
If the infected patient uses an FFP3 mask with a valve, when inhaling, it filters the outside air, but when exhaling, it expels air contaminated with pathogens. The face protection, in the case of patients, must have the capacity to retain the air we exhale. Therefore, the surgical mask is effective for these situations.
Should all respiratory patients wear masks?
Although the device must ensure proper ventilation for the user, not all patients should use it. Depending on the type of pathology, respiratory patients may have contraindications for wearing a protective mask. Therefore, any specific questions should always be resolved by a medical professional.
Can I make my own surgeon-type mask?
Given the difficulty of acquiring an approved protective mask, the general public can choose to make their own homemade versions. For it to be effective against coronavirus, we must follow the recommended guidelines for its preparation and when its use is indicated. These measures do not protect the user wearing them but are very useful for slowing the spread of the virus by helping asymptomatic people prevent the virus from being transmitted to others.
What is PPE?
PPE is Personal Protective Equipment. It is a device or means that a person will wear or have at their disposal, with the aim of protecting them against one or more risks that may threaten their health and safety. For example, gloves, mask, gown...
Are there other routes of transmission?
In addition to droplet transmission, contact transmission can occur. This happens directly when we have contact with a patient, or indirectly when we are exposed to contaminated elements, such as objects, food, or other items previously in contact with the microorganism.
The third route of transmission is airborne. This is caused by droplets smaller than 5 microns, which contain pathogens and can remain in the air for long periods and be transmitted over distances greater than one meter. In this case, exposed individuals should use high-risk masks.
It should not be forgotten that this is a preventive measure and that we will always need to maintain proper hand hygiene for these guidelines to be effective. As well as not touching your face, correctly donning medical products (masks, gloves, gowns), and carrying out proper disinfection and cleaning of elements that may have been exposed.
